Sterilization of water, especially in countries where sanitation is still at a primitive level, is important in the prevention of disease. Travelers are especially susceptible to the development of diarrhea. According to Drug Therapy, July 1988, 10 to 15 million Americans travel abroad each year, and 25% of these travelers become ill. It has been estimated that as many as 40% of patients traveling to South American countries develop diarrhea. This has been proven to be preventable by antimicrobial prophylaxis. Some physicians have prescribed antibiotics on a prophylactic basis. Therefore a simple method of sterilizing water is needed so that people can drink ordinary tap water when bottled water is not available.
Iodine is superior to chlorine, as a biocidal agent, yet chlorine is the major component used for the sterilization of water. There is less reactivity of iodine with organic matter and there is also much less microcidal variation over a wide pH range. In addition, chlorine forms chloramines in the presence of ammonia while iodine does not form iodamines. The absence of reactivity with ammonia is important in the sterilization of swimming pools where ammonia can be present in significant quantities. Two parts per million of iodine is innocuous to fishes, is harmless to the eye when introduced into the human eye, and can be ingested by mouth in large quantities without any serious sensation or discomfort. The cornea and sclers of the eye are far less sensitive to irritation by 2 to 5 parts per million of iodine in normal saline than they are to comparable germicidal concentrations of chlorine. Iodine is rapidly inactivated by the body tissues by the conversion of iodine to iodide (Dialysis and Transplantation, June 1979, page 590). Iodine concentrations in 2 to 5 parts per million are highly bacteriocidal and produce an imperceptible discoloration of water. The taste of the water is also not disagreeable, though there might be a slightly strange taste to the treated water. The efficacy of iodine as a sterilant for drinking water has been adequately proven in the past (Industrial Engineering Chemistry, 45:1009, 1953; also Journal of the American Pharmaceutical Association, Scientific Ed. 47:417, 1958). Iodine has been shown to be superior to chlorine for the disinfection of swimming pool water (American Journal of Public Health, 49:1060, 1959; also Public Health Report, 78:393, 1963; for the comparison of iodine and chlorine as swimming pool disinfectants, see American Journal of Public Health, 60:535, 1970).
In a previous patent, U.S. Pat. No. 4,361,380, the present patentees describe the complexing of iodine with polyurethane and the surface liberation of iodine which would prevent pathogenic bacteria from growing on it.